Toxins in the environment might make you older than your years

Why are some 75-year-olds downright spry while others can barely get around? Part of the explanation, according to research from the University of North Carolina at Chapel Hill, is differences from one person to the next in exposure to harmful substances in the environment, chemicals such as benzene, cigarette smoke and even stress.

While the birth date on your driver’s license can tell you your chronological age, that might mean little in terms of the biological age of your body and cells. The researchers, including UNC Lineberger Comprehensive Cancer Center Director Ned Sharpless, say that what we need now is a better understanding of the chemicals involved in aging and biomarkers to measure their effects.

“The rate of physiologic, or molecular, aging differs between individuals in part because of exposure to ‘gerontogens’, i.e., environmental factors that affect aging,” said Sharpless, whose work appears today in Cell Press journal Trends in Molecular Medicine. “We believe just as an understanding of carcinogens has informed cancer biology, so will an understanding of gerontogens benefit the study of aging. By identifying and avoiding gerontogens, we will be able to influence aging and life expectancy at a public health level.”

From a public health perspective, cigarette smoke is likely the most important gerontogen, Sharpless said. Cigarettes are linked with cancers but also with atherosclerosis, pulmonary fibrosis, and other diseases associated with age. UV radiation from the sun makes us older too, and Sharpless and his colleagues recently showed that chemotherapy treatment is also a strong gerontogen.

The researchers call for a concerted research effort to understand the clinical uses for molecular tests of aging as well as the epidemiology of accelerated aging.

“We believe the comparison of molecular markers of aging to clinical outcomes should begin in earnest,” Sharpless said. For example, he asked, can biomarkers to aging predict toxicity from surgery or chemotherapy in patients in whom chronological age is already a known risk factor?

Sharpless does caution against making tests of molecular age available to consumers and patients directly. “The potential for miscommunication and other harm seems real,” he said.

Published May 28, 2014.